MARINE ISOPODA OF NEW ENGLAND, ETC. 379 



Plates IX and X, Figs. .''>S-G3. 



This species may be most readily recognized among our Isopoda by 

 tlie distinct thoracic and abdominal segments, tbe small lateral eyes, 

 and tbe evident distinction, in both antennnlfc and antennae, of pedun- 

 cle and flagellnm. From tbe next species it is distinguished by tbe tip 

 of tbe telson, wbicb is truncated, or sligbty emarginate, and grooved on 

 tbe median line above near tbe end. 



Tbe body is, wben extended, about three times as long as broad, and. 

 is smooth and polished throughout. The bead is quadrate, a little broader 

 in front than behind, and embraced at tbe sides by tbe first thoracic 

 segaaent. Tbe eyes are triangular, with the angles rounded, and are 

 often partially covered below by tlie projecting anterior lobes of tbe first 

 thoracic segment. They are separated by about three times their long- 

 est diameter. Tbe antenuulfc (pi. X, fig. CO) are robust, witb their 

 basal segments in contact; tbe first segment is short and sub-spberical j 

 the second also short ; the third cylindrical and as long as the first two 

 taken together and followed by a robust, but short, tapering flageUum, 

 consisting of about fifteen segments, of which the second is as long as any 

 other two, but tbe rest are all short. The flagellar segments beyond 

 the first are provided each with a tuft of " olfactory sette." Tbe antennae 

 (pi. X, fig. Gl a) are longer and more slender than the antennulse, and 

 are separated at their bases. The first four peduncular segments are 

 robust ; the first two short ; the third and fourth each about twice as 

 long as the first or second, and tbe fiftli or last peduncular segment 

 sbgbtly the longest and much tbe most slender. Tbe fourth and fiftb 

 segments bear along tbe distal iiortion of their outer margins long 

 bristle-form hairs. The flagellnm is slender and composed of from 15 

 to 18 segments, eacb bearing a few short bristles. The maxillipeds 

 (1)1. X, fig. 62a) are elongated and almost pediform but flattened; 

 tbe external lamella is small and subtriangular, rounded and hairy at 

 the tip; the palpus is five-jointed, with the last four segments broad, 

 flattened, and Avell ciliated ; tbe tip of the maxilliped, nearly concealed 

 by the large palpus, is provided witb very densely i)lumose bristles. 

 The outer maxillae (pi. X, fig. Gl b) are short and robust ; the two articu- 

 lated lobes narrow ovate, rounded at tbe tip, armed, especially tbe inner 

 one, with spines and plumose or pectinated bristles. The inner maxillae 

 (pi. X, fig. Gl c) are robust, witb the outer lobe armed witb strong smootb 

 spines; the inner lobe rounded at the end and bearing three straigbt 

 rather blunt spines, densely covered toward the tip witb soft hairs. 

 The mandibles (pi. X, figs. Gl d) are robust and horny at tbe tip, armed 

 with one strong acute tooth, and in tbe right mandible witb one acute 

 and one obtuse tooth along a cutting edge, while tbe left mandible has 

 three less acute teeth along this edge. Each mandible is, moreover, 

 provided with a molar process or area (m), on its inner surface set along 

 its interior and upper margin witb spines. A narrowly lanceolate leaf- 

 bke appendage is attached just below tbe molar area. This appendage 



